In PowerShell v.2, all new modules work like libraries and can be loaded using Import-Module to gain access to all public functions, variables, aliases etc. like this:
Import-Module path_to_module\mymodule.psm1
A better way is to store a reference to your module in a variable which requires the -passthru parameter:
$module = Import-Module path_to_module\mymodule.psm1 -passThru
$module | Get-Member will show you all the useful methods you can now access. For example, it tells you just which functions, aliases, variables, etc. are available from this module.